Cooking Appliance for Commercial Kitchens Comprising a Fat Extraction Device, Fat Extraction Device and Method for Operating Such a Cooking Appliance with Fat Extraction

ABSTRACT

A cooking appliance for commercial kitchens has a fat collection device with at least one fat collection container, at least one fat extraction line, at least one suction pump and at least one fat discharge line. The fat extraction line extends from the fat collection container to the suction pump. The suction pump conveys a fat-water mixture via the fat extraction line into the fat discharge line. A cleaning device is provided which conveys water at least via the fat extraction line and the fat collection container into a cooking chamber outlet of the cooking appliance.

BACKGROUND OF THE INVENTION

The present invention relates to a cooking appliance for commercial kitchens in the form of a combi-steamer or a rotisserie appliance comprising a fat extraction device.

Cooking appliances for commercial kitchens can have large or very large cooking chambers which are suitable for receiving a large quantity of food to be cooked. When cooking fatty food, such as for example poulards, ducks, geese, chickens, etc., this results in a relatively large quantity of fat leaking from the food. This fat leaking from the food to be cooked together with liquid contained in the food, in particular with water, forms so-called vapours or waste steam when being removed from the cooking chamber together with discharged gaseous cooking chamber atmosphere. These vapours are discharged from the cooking chamber via a drain opening for the disposal thereof.

In the appliances of the prior art, hot vapours from the cooking chamber are supplied to a siphon device with steam condensation, on the one hand, in order to condense the steam and, on the other hand, to cool it together with the fat-water mixture of the vapours. Cooling to a predetermined value is required since liquid should only be introduced into the wastewater system of a building connection at a maximum temperature which is generally below that of the vapours discharged from the cooking chamber.

U.S. Pat. No. 7,677,163 B2 discloses a cooking appliance comprising a cooking chamber outlet and a siphon device having a water reservoir located therein which serves to prevent odours or steam from passing out of the wastewater system into the cooking chamber. The water reservoir also serves for cooling the hot vapours.

In certain cooking appliances, as specified above, a large quantity of fat leaking from the food to be cooked is produced which can result in problems in terms of disposal via the building connection to the wastewater system. Moreover, this natural fat is suitable for further processing, for example in the production of cosmetics, such as soap, or fuel and, therefore, contributes to sustainability during processing of such raw materials.

A cooking appliance is disclosed in U.S. Pat. No. 8,997,730 B2 in which there is the possibility of recovering fat by means of fat extraction. In this cooking appliance, the vapours are discharged via a drain opening and a short pipe connector into a siphon device which is located therebelow and in which a water reservoir is located. A vapour collection container is located below the drain opening, wherein the vapour collection container is separated from the water reservoir. This collection container has a drain opening connected to a fat extraction line through which the fat-water mixture can be extracted by means of a suction pump into a storage tank.

After the respective cooking process has been completed, or after a plurality of cooking processes have been completed, the cooking chamber has to be cleaned for hygiene reasons. This can be carried out manually, by a corresponding cleaning agent being introduced into the cooking chamber, manually distributed, and flushed out again by supplying water. In operation of commercial kitchens, however, automatic cleaning devices have proved particularly advantageous. In any case, a liquid (powder-dissolved or otherwise dissolved) cleaning agent is produced as a result of the cleaning, the cleaning agent having to be removed entirely from the cooking chamber of the cooking appliance and further cooking appliance components to be cleaned, for hygiene reasons, before a further cooking process can be carried out.

The same elements and devices of the cooking appliance are used for the discharge of the cleaning liquid together with corresponding dissolved residues of the cooking process, as for the drainage of the vapours. In the above-mentioned prior art, this leads to the significant drawback that the cleaning agent, which is mixed with the dissolved residues from the cooking chamber, also passes into the vapour collection container and is also extracted. Residues of the cleaning agent thus pass into the collected fat and significantly contaminate this collected raw material for the further processing thereof.

SUMMARY OF THE INVENTION

It is an object of the present invention to avoid the drawbacks described above and to propose a cooking appliance for commercial kitchens in the form of a combi-steamer or a rotisserie appliance comprising a fat collection device and a fat recovery system which substantially avoid that cleaning residues are able to penetrate into the recovered fat or mix with same. Moreover, it is also an object of the present invention to propose a corresponding fat collection device for a commercial kitchen cooking appliance. Finally, it is also an object of the present invention to propose a method for operating a commercial kitchen cooking appliance, in particular a combi-steamer or a rotisserie appliance, comprising a fat recovery system in which a contamination of the recovered fat by cleaning agent is substantially avoided.

To solve this object, the present invention proposes a cooking appliance for commercial kitchens in the form of a combi-steamer comprising a cooking chamber for cooking food to be cooked arrangeable on a plurality of cooking levels, or in the form of a rotisserie appliance comprising a cooking chamber for cooking food to be cooked arrangeable on a rotatable support for food to be cooked, the cooking appliance comprising a heating device for heating a cooking chamber atmosphere, an appliance controller for controlling the cooking appliance, and a cooking chamber outlet located below a floor of the cooking chamber and provided for draining off a fat-water mixture and gaseous components of the cooking chamber atmosphere from the cooking chamber, wherein the cooking chamber outlet extends from a drain opening in the floor or in the floor region of the cooking chamber to a siphon device, wherein a fat collection device is provided, the fat collection device comprising at least one fat collection container, at least one fat extraction line, at least one suction pump and at least one fat discharge line, wherein the fat extraction line extends from the fat collection container to the suction pump, wherein the suction pump is configured to convey the fat-water mixture extracted via the fat extraction line into the fat discharge line, and wherein a cleaning device is provided, the cleaning device being configured to convey water at least via the fat extraction line and the fat collection container into the cooking chamber outlet in a direction towards the siphon device.

As a result, it is advantageously achieved that residues of a cleaning agent are flushed out of the fat extraction line and out of the fat collection container and discharged to the siphon device so that fat produced in a subsequent cooking process can be recovered without residues of the cleaning agent. This significantly increases quality of the recovered fat and substantially contributes to the reusability of this fat.

As a result, an appropriate price for the further processable raw material can also be achieved by an operator of a commercial kitchen which, with retrospective effect, brings down the purchase price of the food to be cooked.

The structural design of the fat collection container being arranged upstream of the siphon device, more specifically between the drain opening and the siphon device, results in the great advantage of a content of fat in the cooking chamber drainage introduced into the siphon device is significantly reduced, wherein, in addition, a content of fat in an exhaust air pipe is also significantly reduced. As a result, the service life of the cooking appliance and its components, such as a drainage pump of the siphon, a circulating pump of the cleaning system, as well as as seals, in particular of pumps, water supplies of the cleaning system or even the temperature sensor, can be significantly increased.

Additionally, compared to commercial kitchen cooking appliances without a fat recovery system the great advantage is maintained, in that a separation of the fat upstream of the drainage of the cooking chamber drain into the drains of a building is superfluous.

This also results in the advantage that no change of already existing cooking processes is required and also that a cooking result is not impaired by the fat collection device according to an aspect of the invention. Thus, the cooking quality is not affected.

As the fat collection container is preferably located in an initial region of the cooking chamber outlet, fat extraction can be performed at an early stage and the further flow path towards the siphon device is freed of fat contamination at an early stage. For example, an initial portion of the fat collection container is arranged within a distance of 80 mm to 120 mm from a centerline of the drain opening of the cooking chamber, preferably at a distance of 30 mm to 40 mm from the centerline of the drain opening.

Advantageously, the cooking chamber outlet and the fat collection container are formed from metallic material which is particularly temperature-resistant, and the fat collection container is welded to the cooking chamber outlet. This results in a durable connection of the fat collection container to the cooking chamber outlet, avoiding potentially non-permanent seals, wherein the connecting region is particularly difficult to reach due to the installation location below the cooking chamber.

Accordingly, it is also advantageous that the fat extraction line, which can comprise a fat extraction pipe which is preferably made of metal, is welded onto the fat collection container. As a result, a particularly durable connection which is substantially free of maintenance is provided.

Alternatively, at least the fat collection container is formed from a plastics material, optionally also the cooking chamber outlet and/or the fat extraction line. In this case, the fat collection container can be configured integrally with the cooking chamber outlet or joined thereto.

As an end portion of the fat collection container is preferably configured in a ramp-shaped manner in a direction towards the siphon device, the advantage of a streamlined design of the fat collection container and its connection to the cooking chamber outlet is achieved. The ramp-shaped end portion of the fat collection container is preferably a portion arranged closer to the siphon device than to the drain opening in a direction parallel to a longitudinal axis or central axis of the cooking chamber outlet in the region of the fat collection container. When flushing through the cleaning device for cleaning the fat collection device, the fat collection container is flushed through in a direction towards the siphon device and the flushed-through water is conducted into the siphon device. The discharge process is assisted or facilitated by the ramp-shaped design of the end portion.

The ramp-shaped end portion is inclined at least in some portions relative to the longitudinal axis or central axis of the cooking chamber outlet. Various embodiments are possible for the design of the ramp-shaped end portion. For example, the end portion is formed by three side surfaces which are inclined toward one another. Alternatively, the ramp-shaped end portion can be formed in a conical shape. In a further alternative embodiment, the fat collection container can be configured as an inclined and/or conical pipe or a pipe portion, respectively, which tapers in the direction of the siphon device.

Advantageously, a branch line for draining off gaseous components of a fluid or vapours discharged from the cooking chamber into the cooking chamber outlet, i.e. of the fat-water mixture and the gaseous components of the cooking chamber atmosphere, branches off the cooking chamber outlet between the fat collection container and the siphon device. As a result, advantageously the cooling capacity of the siphon device can be lower.

In this context, it is advantageous for the branch line to comprise a first portion extending substantially horizontally with a slight inclination of 1° to 5°, preferably 2° to 2.5°. In general, hot exhaust air from the cooking chamber also contains fat components in the form of fat droplets and this exhaust air partially condenses in the branch line. Due to the slight inclination a return flow of this condensate, optionally comprising fat components, back into the cooking chamber outlet can be achieved. The inclination is thus preferably defined by the branch line in a direction of flow from the cooking chamber outlet.

It is also advantageous that the fat extraction line extends from the fat collection container to the suction pump at least partially at a slight inclination of 1° to 5°, preferably 1.5° to 2°. As a result, it is achieved that a return flow of the fat-water mixture into the fat collection container is substantially prevented.

A further advantage can also be achieved in that the fat extraction line and the first portion of the branch line are arranged at a small spacing from one another, preferably adjacent to one another. This results in the advantage that the closer the branch line is located to the fat extraction line, the greater the heat transfer from the branch line, which is heated up by the exhaust air, to the fat extraction line, whereby a solidification of the fat flowing through the fat extraction line can be significantly reduced and the fluidity thereof is assisted by the transferred heat. The small spacing is thus preferably selected such that a heat transfer occurs between the branch line and the fat extraction line. The spacing can be in the region of a few centimetres, preferably between 0 cm and 5 cm, more preferably between 0 cm and 3 cm, even more preferably between 0 cm and 1 cm. A spacing of 0 cm corresponds to an embodiment in which the branch line and the fat extraction line are arranged adjacent to one another, as described above.

It is also advantageous that the suction pump is configured as a pump which can be flowed through in both directions, whereby it can be flowed through against a pumping direction. The suction pump conveys the fat-water mixture from the fat collection container into the fat discharge line. In particular when a pump inlet cannot be closed, there is the possibility of cleaning liquid penetrating into the pump and collecting therein. Since it is also possible for the suction pump to be flowed through against the pumping direction, there is the possibility of flushing through the suction pump. Thus, potentially collected residues of cleaning liquid can be removed again.

In a preferred embodiment of the present invention, the fat discharge line comprises a riser pipe arranged at a pump outlet of the suction pump or connected thereto, the riser pipe extending upwardly from there over a certain distance. Two advantages are associated therewith. Firstly, a penetration of cleaning liquid into the riser pipe up to the level of the drain opening in the cooking chamber of the cooking appliance is limited and, on the other hand, the extracted fat-water mixture is conveyed sufficiently far upwardly such that it can flow into a fat storage tank for collecting the extracted fat or the fat-water mixture. Even if, in a space-saving design, the riser pipe is arranged substantially vertically upwardly, oblique arrangements of the riser pipe are also possible within the context of the invention.

Advantageously, the cleaning device comprises a water supply for cleaning the fat collection device. Cooking appliances, in particular combi-steamers, usually have a water supply to generate steaming of the cooking chamber. This is carried out by generating steam in the cooking chamber or by introducing steam from outside the cooking chamber. Water is also required for cleaning the cooking chamber, for example via a hand shower or by an automatic cleaning system. In an advantageous embodiment, the water supply of the cooking appliance forms at the same time the water supply of the cleaning device. However, it is also conceivable that the cleaning device comprises a further water supply or can be connected to an external water source.

It is also advantageous that the water supply of the cleaning device for cleaning the fat collection device comprises at least one water supply line leading into the riser pipe above the suction pump. Thus, a line section, including the suction pump, potentially containing cleaning liquid can be flushed through and freed from residues of cleaning liquid in a reliable manner.

If the suction pump has a closable pump inlet, a penetration of cleaning liquid into the suction pump can be avoided by closing this pump inlet. As a result, advantageously the possibility is also provided of connecting the water supply line of the water supply of the cleaning device directly in front of the pump inlet in order to initiate a flushing-through of the fat extraction line and the fat collection container from that point.

It is also advantageous that the water supply of the cleaning device for cleaning the fat collection device has at least one further water supply line. Thus, in addition to the water supply line leading into the riser pipe, a further water supply line which leads directly into the fat collection container can be provided and/or a further water supply line which leads into the fat extraction line directly in front of the suction pump can be provided.

The water supply is provided with at least one valve, in particular a solenoid valve, which controls the supply of fresh water to the at least one water supply line. A plurality of solenoid valves control the water supply to a plurality of water supply lines.

In one embodiment, the suction pump can advantageously be arranged at a height which is above the height of the drain opening in the floor or floor region of the cooking chamber of the cooking appliance, wherein an outlet end of the fat extraction line is connected to the pump inlet via a connecting line. The advantage is associated therewith that cleaning liquid never passes to the suction pump and, thus, the suction pump does not have to be subsequently freed of the cleaning liquid. Therefore, it can be sufficient to flush through at least partially the fat collection device upstream of the suction pump, in particular the fat extraction line and the fat collection container. In order to remove deposits from the system, however, it can also be desirable in this embodiment to flush through the suction pump and optionally the fat discharge line, as described above.

Alternatively, it is possible to arrange the suction pump between the cooking chamber floor and the appliance floor or even below the appliance floor.

During operation of the cleaning device of the cooking appliance, the suction pump is not in operation. Thus, an intake of cleaning agent into the suction pump is avoided.

Moreover, the suction pump is not in operation during operation of the cleaning device for cleaning the fat collection device, whereby the flushing through the suction pump is not affected, in particular when the water is supplied behind the suction pump, for example into the riser pipe.

A further advantage of the present invention is that a heating device is provided on or in the fat collection container by means of which liquid non-fat components of the fat-water mixture drained from the cooking chamber being able to be evaporated. As a result, the advantage is achieved that the water component in the fat-water mixture is further reduced and, thus, the concentration of fat can be increased in the recovery process.

It is also advantageous that the fat collection device has a shut-off valve at an inlet of the water supply, in particular of the at least one water supply line, into the fat extraction line, such that, after shutting off the fat extraction line, the cleaning device can clean the suction pump and the fat discharge line by flushing through. This can be provided in addition to the water supply line which leads into the fat discharge line, in particular into the riser pipe, behind the suction pump or can be connected thereto. The shut-off valve can advantageously be a multi-way valve which can take a position in which the fat extraction line and the fat collection container are flushed through, and which can take a different position in which the suction pump and the fat discharge line are flushed through. Optionally, the shut-off valve can also be configured to permit flushing in both directions at the same time. In this case, it can be sufficient to provide only a single water supply line.

In one embodiment, the cleaning device comprises a water supply line connected to the fat discharge line, in particular to a discharge pipe or a shut-off valve of the fat discharge line. This water supply line can also be denoted as a connecting line or connecting hose. In other words, the water supply line can be connected to the end of the fat discharge line which is not connected to the suction pump. The water supply line or connecting line can be connected to an external water source, for example to a water pipe or a water tap. Preferably, a first end of the water supply line or connecting line is connected to the fat discharge line and a second end of the water supply line or connecting line opposite to the first end can be connected to the external water source. Preferably, the water supply line or connecting line, in particular the second end thereof, can also be connected to the fat storage tank. The fat storage tank has to be changed at regular intervals and, thus, generally is easily accessible. Consequently, this also applies to the second end of the water supply line or connecting line, which as a result can be gripped easily by a user and connected to the water source. In this manner, there is the possibility of flushing through the entire fat collection device in a simple manner.

With intensive and/or lengthy use of the cooking appliance the risk can occur that fat is deposited at unfavorable places. Advantageously, the water of the cleaning device, which is used for flushing, can be heated for cleaning the fat collection device, whereby solidified fat can be dissolved and flushed out.

The partial object set forth above is also achieved by a fat collection device for commercial kitchen cooking appliances, in particular combi-steamers or rotisserie appliances, the fat collection device comprising at least one fat collection container, at least one fat extraction line, at least one suction pump and at least one fat discharge line, wherein the fat collection container is arrangeable on a cooking chamber outlet of the cooking appliance in the vicinity of a drain opening in the floor or in the floor region of the cooking appliance, wherein the fat extraction line extends from the fat collection container to the suction pump, wherein the suction pump is configured to convey the fat-water mixture extracted via the fat extraction line into the fat discharge line, and wherein the fat collection device comprises a cleaning device configured to convey water at least via the fat extraction line and the fat collection container into the cooking chamber outlet in a direction towards a siphon device at the end of the cooking chamber outlet of the cooking appliance.

It is therefore possible to integrate a fat collection system in cooking appliances in which a recovery of fat, or optionally other materials, is possible by corresponding extraction.

Finally, according to another aspect of the present invention a method for operating a commercial kitchen cooking appliance, in particular a combi-steamer or a rotisserie appliance, and for collecting fat produced during a cooking process, comprises the steps of:

-   -   collecting a fat-water mixture escaping from a cooking chamber         of the cooking appliance, via a drain opening thereof, within a         fat collection container of a fat collection device connected to         a cooking chamber outlet of the cooking appliance,     -   extracting the fat-water mixture via at least one fat extraction         line from the fat collection container by means of a suction         pump arranged at the end of the fat extraction line,     -   discharging the fat-water mixture extracted by the suction pump         via a fat discharge line to a fat storage tank, and     -   carrying out a cleaning process of the fat collection device         after completing a cleaning process of the cooking appliance, by         conveying water in a reverse direction to an extraction         direction at least through the fat extraction line and the fat         collection container into the cooking chamber outlet in a         direction towards a siphon device at an end of the cooking         chamber outlet of the cooking appliance.

Advantageously, an operation of the suction pump is performed in a clocked manner. The clocking can be pre-set or changed during the course of the cooking program or the cooking process. For example, an extraction is performed by pumping out in a 60 second cycle: 30 seconds pumping out and 30 seconds pause. With certain cooking steps, a continuous operation is also possible. On the other hand, a clocking below 50% is also possible, i.e., a pumping out duration is shorter than the pause.

Thus, it is also advantageous that the is performed as a function of the food to be cooked and/or the cooking process. Thus, the suction power can be adapted to the fat which is produced, for example depending on the food to be cooked (for example duck, goose) and/or by the quantity loaded into the cooking chamber and/or the course of the cooking process.

It is also advantageous that the cleaning process of the fat collection device is performed both at the beginning and at the end of the cleaning process of the cooking appliance. Performing the cleaning process at the beginning advantageously provides a removal of the remaining fat-water mixture before penetration of the cleaning agent drained off the cooking chamber during the cleaning process of the cooking appliance, and carrying out at the end removes the remaining cleaning agent.

As the fat collection device is flushed through at the beginning of the cleaning process of the cooking appliance, the fat collection device is flushed with fresh water and, after the flushing process is completed, a part of the fresh water remains in the fat collection container, in the fat extraction line, in the suction pump and in a portion of the riser pipe. If the cleaning of the cooking appliance is now triggered, the water present in the fat extraction line hinders a penetration of the cleaning agent into this fat extraction line.

With the next fat extraction process, after having previously flushed through the fat collection device again, the existing fresh water is conveyed into the fat storage tank and only then is the extracted fat introduced therein, however, due to the natural separation between fat and water, the water collected at the bottom of the storage tank can be correspondingly discharged and the fat which is separated therefrom remains within the storage tank.

In an advantageous embodiment, the cleaning process of the fat collection device is carried out automatically. For example, the cleaning process of the fat collection system is automatically initiated as soon as the cleaning process of the cooking appliance is to be started, for example by a corresponding user input, and/or as soon as the cleaning process of the cooking appliance is completed. It is possible to implement the cleaning process of the fat collection device automatically in a particularly simple manner when the cleaning device is connected by means of the water supply line to the water supply of the cooking appliance, as described above.

Additionally or alternatively, during the cleaning process of the fat collection device, water can be conveyed through the discharge line, preferably through the entire fat discharge line, the fat extraction line and the fat collection container into the cooking chamber outlet. This can be carried out particularly easily when the cleaning device comprises the water supply line or connecting line which can be connected to the fat discharge line and a water source, preferably an external water source, as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a cooking appliance in the form of a combi-steamer;

FIG. 2 shows a further perspective view of the cooking appliance of FIG. 1 with the cooking chamber door removed;

FIG. 3 shows a perspective view of a cooking appliance in the form of a large combi-steamer with a rack trolley;

FIG. 4 shows a schematic view of a construction of an embodiment of the cooking appliance in the form of a combi-steamer;

FIG. 5 shows a perspective view of a cooking chamber outlet and a partial view of a fat collection device with a fat extraction line;

FIG. 6 shows a view of a rear face of the cooking appliance in the form of a combi-steamer with a fat suction pump, a fat discharge line and a water supply of the cleaning device of the fat collection device; and

FIGS. 7 a, 7 b show a view of the rear face of the cooking appliance according to FIG. 6 with a variant of the cleaning device.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

In the figures, same elements are provided with same reference sings.

A conventional cooking appliance 1 in the form of a combi-steamer comprising a cooking chamber 3 for cooking food products is shown in FIGS. 1 and 2 , wherein the cooking chamber 3 can be closed by a cooking chamber door 5. The cooking chamber door 5 has a door handle 8 for the handling thereof. A so-called technical space 6 is located adjacent to the cooking chamber 3, wherein a drive device for a fan wheel 7, an appliance controller having a display and control panel 9, and a hand shower 11 comprising a hand shower head 13 are arranged within the technical space 6.

As can be seen, the hand shower head 13 is arranged so as to be received in a niche-like receptacle 19 and, in the resting position shown in FIGS. 1 and 2 , does not protrude over a front face of the cooking appliance 1. Due to the niche-like receptacle 19 the hand shower head 13 can be easily gripped and can be pulled out together with a part of a supply line (not shown). The cooking appliance 1 has a water supply to which the hand shower 11 is connected, wherein water can be sprayed via the hand shower 11 into the cooking chamber 3, for example for performing a manual cleaning process.

As is also visible from FIG. 2 , the cooking chamber 3 has a drain opening 15 in the region of its floor 4, wherein not only a fat-water mixture formed by condensed water and the fat released from the food to be cooked during the cooking process can stream out or flow out through said drain opening, but also a gaseous cooking chamber atmosphere, all together forming the vapours defined herein, and a cleaning medium generated in the course of a cleaning process or a generated cleaning or washing liquor are able to be removed from the cooking chamber 3 through said drain opening.

Indicated schematically, an internal temperature sensor 17 of the cooking appliance 1, which in the exemplary embodiment shown serves as a core temperature sensor, is also located on the floor 4 of the cooking chamber 3.

An exhaust air outlet 21, to which an exhaust air pipe leads, is visible on the upper face of the cooking chamber 1. This is described in greater detail below.

Whilst in FIGS. 1 and 2 a cooking appliance 1 of a relatively small overall size is shown, in FIG. 3 a cooking appliance 1′ of a large overall size is shown. Visible through a transparent door glass 20 of the cooking chamber door 5 is a (suspension) frame 29 comprising a plurality of insertion rails 31 which serve to receive a number of insertion plates or insertion grids forming insertion levels, loaded with the food to be cooked, as suitable or desired for the respective cooking process. A corresponding frame 29 is located on the opposing side, and both frames 29 are part of a rack frame of a rack trolley 23 known per se. This rack trolley 23 has a rectangular frame 25 on which a roller 27 is provided at each corner, wherein at least two of the rollers 27 are rotatable. As visible from FIG. 3 , the frame 29 has twenty insertion rails 31, which provides the possibility of receiving a large quantity of food to be cooked on up to twenty insertion levels. The cooking appliance 1′ in turn rests on four corner columns 14.

Advantageously, for example, a collection tray or collection pan (not shown) having a slightly downwardly offset opening can be inserted on the lowest insertion rails on both sides, whereby the liquid fat flows toward this opening, which in the inserted state of the collection pan comes to rest above the drain opening 15. As a result, the fat dripping from above can be collected and conducted to the drain opening 15 and drain therein, whereby the cooking chamber floor 4 of the cooking appliance is covered to a significantly lesser degree with fat. As a result, the floor 4 of the cooking chamber 3 does not have to be cleaned as intensively, which significantly simplifies the cleaning of the cooking chamber 3.

If a large quantity of fatty food to be cooked, such as for example ducks or geese, is cooked in such a large cooking appliance 1′, a correspondingly large quantity of released fat is produced.

In FIG. 4 a construction of the two cooking appliances 1 and 1′ illustrated is shown schematically, wherein the size ratios of the individual components are not shown true to scale but only schematically. Since the two cooking appliances are combi-steamers, there are a plurality of insertion levels 32 for correspondingly receiving food to be cooked. The fan wheel 7 is driven by the drive device in the form of a motor 12, whereby the air or cooking chamber atmosphere 22 can be circulated in the cooking chamber 3.

The drain opening 15 is formed in the floor 4 of the cooking chamber 3, wherein a cooking chamber outlet 33, which extends on the lower face of the cooking chamber 3 to a siphon device 35 and leads into same, is connected to said drain opening 15. The siphon device 35 has a siphon container 36 in which a water reservoir 37 is located. As known from the prior art, a separating plate 41 extending into the water reservoir 37 is provided in the siphon container 36. As a result, an odour seal is formed relative to the cooking appliance drain 43 which is connected to the drains of the building. A drainage channel 44 leads out of the siphon container 36 into the drains (not shown).

Shown schematically is a water supply 45 supplied with fresh water according to arrow 47, wherein the fresh water can be fed via a water supply line 49 into the siphon container 36. A drainage pump 51, to which a drain line 53 is connected, is provided for emptying the siphon container 36, the water reservoir 37 being able to be pumped out via the drain line 53 into the drains 44. After the siphon container 36 is emptied, fresh water can be fed via water supply line 49 of the water supply 45 into the siphon container 36 in order to form the water reservoir 37 again.

The cooking appliance 1, 1′, shown schematically in FIG. 4 , has an automatic cleaning device of the cooking appliance which comprises a supply line 55 by which liquid from the water reservoir 37 can be introduced into the cooking chamber 3 by means of a circulating pump 57. The water reservoir 37 serves for condensing exhaust air, which is supplied via the cooking chamber outlet 33 to the siphon device 35, wherein corresponding vapour components also reach the water reservoir 37 and act thereon. Thus, for performing the automatic cleaning of the cooking appliance, the water reservoir 37 is emptied by means of the drainage pump 51 and fresh water is supplied via the water supply line 49. The fresh water can then serve as an initial liquid for automatic cleaning and, if required, supplied repeatedly to the cooking chamber 3 by means of the circulating pump 57.

Moreover, such an automatic cleaning device of a combi-steamer is known from the prior art and thus is not described further.

According to an aspect of the present invention, the cooking appliance 1, 1′ comprises a fat collection device 59 comprising a fat collection container 61 which is arranged below the cooking chamber outlet 33, as shown in FIG. 4 , which is preferably welded to the cooking chamber outlet 33. A connection opening 71 for a fat extraction pipe being part of a fat extraction line 73 is shown in dashed lines. Other connecting options providing a permanent connection of the cooking chamber outlet 33 and the fat collection container 61 fall within the scope of the invention.

Reference is now made to FIG. 5 in which a part of the fat collection device 59 according to an embodiment of the present invention is shown in a perspective view.

For connecting the cooking chamber outlet 33 to the cooking chamber 3, the cooking chamber outlet 33 has a cooking chamber outlet entry 34 with a connecting flange 38 which can be screwed to the cooking chamber floor 4. In the embodiment shown, to which the invention is not limited, the fat collection container 61 welded to the tubular cooking chamber outlet 33 is located in the vicinity of the cooking chamber outlet entry 34. As clearly visible in FIG. 5 , the fat collection container 61 has a ramp-shaped end portion 62. Details thereof are described in greater detail below.

As shown in FIGS. 4 and 5 , the cooking chamber outlet 33 terminates in a connection opening 58 for connecting to the siphon container 36 of the siphon device 35.

As is also shown in FIGS. 4 and 5 , an opening 63 for a branch line 64 for exhaust air from the cooking chamber 3 is located between the fat collection container 61 and the connection opening 58. The opening 63 forms a start of the exhaust air branch line 64 which has a first portion 65, a second portion 67 and a third portion configured as a connecting piece 69. An exhaust air pipe leading to the exhaust air outlet 21 (FIGS. 1 to 3 ) can be connected to the connecting piece 69.

The first portion 65 of the exhaust air branch line 64 extends substantially horizontally or with a slight inclination of 1° to 5°, preferably of 2° to 2.5°. This provides the advantage that steam from the exhaust air condensing therein can flow back again into the cooking chamber outlet 33. The second portion 67 of the exhaust air branch line 64, which is connected thereto, preferably extends in a similar or in the same inclination as the first portion 65. Condensate and optionally also unsolidified fat can flow back from there as well. Moreover, cleaning agent, which may have penetrated into these portions 65 and 66, can flow back again into the cooking chamber outlet 33 and then onward into the siphon device 35 when evacuating cleaning agent from the cooking chamber 3 via the cooking chamber outlet 33.

The fat collection device 59 also comprises fat extraction line 73 which preferably leads to and opens into the lower region of the fat collection container 61 and provides the option that the fat-water mixture collected in the fat collection container 61 can drain into the fat extraction line 73, respectively. This is supported by the fat extraction line 73 extending at a slight inclination of 1° to 5°, preferably of 1.5° to 2°.

Reference is now made to FIG. 6 which shows a perspective view of the rear face 10 of the cooking appliance 1 or 1′ only partially shown. As shown in FIG. 6 , the fat extraction line 73 extends beyond the rear face 10 of the cooking appliance and is connected to a suction pump 77 via a connecting line 75 or a connecting pipe portion 75. The suction pump 77 serves for extracting the fat-water mixture from the fat collection container 61 and for conveying this mixture via a fat discharge line 82 into a fat storage tank 95 (see FIG. 7 a ), such as a cannister, a collecting bin, etc.

The suction pump 77 is connected via a corresponding control and supply cable 79 to the appliance controller, wherein the cable 79 extends from the suction pump 77 via an opening 81 in the rear face 10 of the cooking appliance to the appliance controller.

The fat discharge line 82 comprises a riser pipe 83 which is held on the rear face 10 of the cooking appliance and extends substantially vertically upwardly. A discharge pipe 85 of the fat discharge line 82 is connected to the riser pipe 83, in the exemplary embodiment said discharge pipe extending substantially horizontally and a shut-off valve 87 being provided at an end thereof for shutting off the fat discharge line 82. At the end of the discharge pipe 85, a corresponding connecting hose 96 and/or connecting pipe portion can be connected to the fat storage tank for collected fat or fat-water mixture, as shown in FIG. 7 a.

According to an embodiment of the invention, the cooking appliance 1, 1′ comprises a cleaning device by which at least the fat extraction line 73 and the fat collection container 61 can be flushed through in a direction opposing the direction of the fat extraction device, in order to remove both, residues of the fat-water mixture and residues of the cleaning agent penetrated thereinto during the cleaning process of the cooking appliance, so that a contamination of the extracted fat or fat-water mixture can be avoided as far as possible in the next fat extraction process.

In one embodiment, a water supply line 89 extends from the water supply 45 (FIG. 4 ) through an opening 90 in the rear wall 10 of the cooking appliance. The water supply line 89 leads into the riser pipe 83 at a position above the suction pump 77. With the supply of water via the water supply line 89, therefore, cleaning and flushing through of the fat collection device 59 from above the suction pump 77 can be performed through the riser pipe 83, the connecting line 75, the fat extraction line 73 and the fat collection container 61, wherein, from the fat collection container 61, the flushing and flushed-through quantity of liquid, respectively, is discharged via the cooking chamber outlet 33 into the siphon device 35 in a streamlined manner due to the ramp-shaped end portion 62.

In an alternative embodiment, the suction pump 77 can have a non-return device at its pump inlet 78, the non-return device preventing cleaning agent from the fat extraction line 73 and the connecting line 75 from penetrating into the suction pump 77. Accordingly, the water supply line 89 can lead into the connecting pipe portion 75 directly in front of the pump inlet 78, wherein a flushing through can take place from that point as far as the siphon device 35.

As shown in FIG. 6 , two lateral cover walls 91 are provided, the cover walls 91 being connected to the rear wall 10 of the cooking appliance by means of screws 93 via corresponding holding elements 92 and, thus, permit a box-shaped structure which can be combined with a corresponding cover wall (not shown). Advantageously, the entire arrangement of the suction pump 77 and its connections are accessible for maintenance operations without having to reach into the interior of the cooking appliance.

A further exemplary embodiment of the cleaning device is shown in FIGS. 7 a and 7 b . The cleaning device accordingly comprises the connecting hose 94 which is connected to the fat discharge line 82, in particular to the shut-off valve 87. To this end, the connecting hose 94, at a first end 94 a, can be mounted onto a pipe portion and can be fixed by means of a pipe clip or the like or fastened by means of a screw or bayonet connection to the pipe portion.

On the one hand, the connecting hose 94, as shown in FIG. 7 a , can be connected to the fat storage tank 95 in order to discharge fat therein. Advantageously, the connecting hose 94 is releasably connected to the fat storage tank 95 in order to be able to replace the fat storage tank if required. To this end, a second end 94 b of the connecting hose 94 can have a corresponding connector, for example in the form of a screw or bayonet connection.

The connecting hose 94 can also be configured as a water supply line and can be connected to a water source by means of a water supply line 96, for example a water tap, a pipeline or the like, as indicated schematically in FIG. 7 b . As a result, a user can connect the easily accessible connecting hose 94 in a simple manner to a water source and thus flush through the entire fat collection device 59 for cleaning.

The water supply line 89 is shown in dashed lines in FIGS. 7 a and 7 b , since it can be optionally provided, as is the case with further water supply lines, in order to permit a flexible use or different cleaning options, for example in combination with water supply 45.

The present invention is not limited to the exemplary embodiments shown. For example, a plurality of water supply lines can be provided, at least another water supply line leading directly into the fat collection container 61 and/or the fat extraction line 73.

In a further embodiment, a multi-way valve can be provided upstream of the suction pump inlet 78, the water supplied being able to be conducted either into the connecting line 75 and the fat extraction line 73 or into the suction pump 77 and the fat discharge line 82 connected thereto, successively or at the same time.

In a further embodiment, for example, the riser pipe 83 can be directly connected to the fat extraction line 73 and the suction pump 77 can be arranged at the upper end of the riser pipe 83 and, in particular, at a height which is above the height of the drain opening 15 of the cooking chamber 3. Thus, cleaning liquid is prevented from penetrating as far as to the suction pump 77. The discharge pipe 85 is then connected to the outlet of the suction pump 77.

It is thus achieved by means of the present invention that recovery of fat from the cooking chamber is allowed, the fat being substantially or practically free of cleaning agent, wherein the fat has been released primarily from cooked food products. Hence, the quality of the recovered fat for suitable further processing, for example for cosmetics, is significantly increased.

Additionally, the great advantage is achieved that damaging fat contamination of both, the drainage pump and the circulating pump by fat which has penetrated into the water reservoir, can be significantly reduced, wherein corresponding seals can also be protected. Thus, the durability of the cooking appliance and its service life can be significantly increased.

This also results in the great advantage that a (negative) effect on the cooking quality is avoided. 

1-28. (canceled)
 29. A cooking appliance for commercial kitchens comprising a cooking chamber for cooking food to be cooked, a heating device for heating a cooking chamber atmosphere, an appliance controller for controlling the cooking appliance, and a cooking chamber outlet located below a floor of the cooking chamber and provided for draining off a fat-water mixture and gaseous components of the cooking chamber atmosphere from the cooking chamber, wherein the cooking chamber outlet extends from a drain opening in a floor region of the cooking chamber to a siphon device, wherein a fat collection device is provided, the fat collection device comprising at least one fat collection container, at least one fat extraction line, at least one suction pump and at least one fat discharge line, wherein the fat extraction line extends from the fat collection container to the suction pump, wherein the suction pump is configured to convey the fat-water mixture extracted via the fat extraction line into the fat discharge line, and wherein a cleaning device is provided, the cleaning device being configured to convey water at least via the fat extraction line and the fat collection container into the cooking chamber outlet in a direction towards the siphon device.
 30. The cooking appliance of claim 29, wherein the cooking appliance is a combi-steamer comprising the cooking chamber for cooking food to be cooked arrangeable on a plurality of cooking levels.
 31. The cooking appliance of claim 29, wherein the cooking appliance is a rotisserie appliance comprising the cooking chamber for cooking food to be cooked arrangeable on a rotatable support for food to be cooked.
 32. The cooking appliance of claim 29, wherein the fat collection container is located in an initial region of the cooking chamber outlet.
 33. The cooking appliance of claim 29, wherein an end portion of the fat collection container is configured in a ramp-shaped manner in a direction towards the siphon device.
 34. The cooking appliance of claim 29, wherein a branch line for draining off gaseous components of a fluid or vapours discharged from the cooking chamber into the cooking chamber outlet branches off the cooking chamber outlet between the fat collection container and the siphon device.
 35. The cooking appliance of claim 29, wherein the water of the cleaning device used for flushing the fat collection device is heated.
 36. The cooking appliance of claim 29, wherein the suction pump is configured as a pump which can be flowed through in both directions, whereby it can be flowed through against a pumping direction.
 37. The cooking appliance of claim 29, wherein the fat discharge line comprises a riser pipe arranged at a pump outlet of the suction pump and extending upwardly from there over a certain portion.
 38. The cooking appliance of claim 29, wherein the cleaning device has a water supply and wherein the fat collection device has a shut-off valve at an inlet of the water supply of the cleaning device into the fat extraction line, such that, after shutting off the fat extraction line, the cleaning device can clean the suction pump and the fat discharge line by flushing through.
 39. The cooking appliance of claim 38, wherein the water supply comprises at least one water supply line leading into the riser pipe above the suction pump.
 40. The cooking appliance of claim 29, wherein the fat collection device comprises the cleaning device.
 41. The cooking appliance of claim 29, wherein the cleaning device comprises a water supply line connected to the fat discharge line and connectable to a water source.
 42. A fat collection device for commercial kitchen cooking appliances comprising at least one fat collection container, at least one fat extraction line, at least one suction pump and at least one fat discharge line, wherein the fat collection container is arrangeable on a cooking chamber outlet of the cooking appliance in the vicinity of a drain opening in the floor or in the floor region of the cooking appliance, wherein the fat extraction line extends from the fat collection container to the suction pump, wherein the suction pump is configured to convey the fat-water mixture extracted via the fat extraction line into the fat discharge line, and wherein the fat collection device comprises a cleaning device configured to convey water at least via the fat extraction line and the fat collection container into the cooking chamber outlet in a direction towards a siphon device at the end of the cooking chamber outlet of the cooking appliance.
 43. A method for operating a commercial kitchen cooking appliance and for collecting fat produced during a cooking process, the method comprising the steps of: collecting a fat-water mixture escaping from a cooking chamber of the cooking appliance, via a drain opening thereof, within a fat collection container of a fat collection device connected to a cooking chamber outlet of the cooking appliance, extracting the fat-water mixture via at least one fat extraction line from the fat collection container by means of a suction pump arranged at an end of the fat extraction line, discharging the fat-water mixture extracted by the suction pump via a fat discharge line to a fat storage tank, and carrying out a cleaning process of the fat collection device after completing a cleaning process of the cooking appliance, by conveying water in a reverse direction to an extraction direction at least through the fat extraction line and the fat collection container into the cooking chamber outlet in a direction towards a siphon device at an end of the cooking chamber outlet of the cooking appliance.
 44. The method of claim 43, wherein an operation of the suction pump is performed in a clocked manner.
 45. The method of claim 44, wherein the clocking is performed as a function of the food to be cooked.
 46. The method of claim 44, wherein the clocking is performed as a function of the cooking process.
 47. The method of claim 43, wherein, during the cleaning process, water is conveyed through the fat discharge line, the fat extraction line and the fat collection container into the cooking chamber outlet.
 48. The method of claim 43, wherein the cleaning process of the fat collection device is performed both at the beginning and at the end of the cleaning process of the cooking appliance. 